Grinding wheels are well-known devices for shaping or finishing the edges of planar materials, e.g., glass sheets. A grinding wheel is typically used to shape and finish a rounded or beveled profile into the edge of a glass sheet which is to be used as a door glazing in an automotive vehicle
A grinding wheel generally rotates at a high speed to effect the proper shaping of a workpiece. This results in a considerable undesirable build-up of heat. Moreover, the grinding wheel typically picks up particles of debris abraded from the workpiece which accumulate at the working surface of the grinding wheel thereby substantially diminishing its grinding ability and durability Where the workpiece is a glass sheet, fine particles of glass dust tend to become air borne and settle on the major surfaces of the glass sheet. These particles tend to mar the major surfaces of the glass sheet when they are later removed, e.g., by wiping with a cloth. Additionally, the heat and pressure generated at the grinding interface causes glass dust to adhere to the ground surfaces. This adhered glass dust resists removal during the ground glass sheet washing operation, but comes loose while the ground glass sheet is conveyed through a roller hearth furnace. The falling glass dust contaminates the furnace rolls, which in turn mars the surface of the glass sheet. For these reasons, it is desirable to incorporate a fluid such as, for example, a cooling and/or lubricating fluid at the point of contact between the grinding wheel and the workpiece.
U.S. Pat. No. 3,777,443 to Shaw discloses a segmented grinding wheel, comprising a wheel having a peripheral recess for receiving and securing grinding segments. Additionally, a pair of flanges cooperate with the wheel to define troughs for receiving a cooling fluid. Upon rotation of the grinding wheel, the fluid is urged by centrifugal force through small internal passages from the troughs to the base of the peripheral recess. These small passages, however, can easily become blinded by the particles abraded from the workpiece during the grinding operation, and thereafter must be removed by a reaming operation to reestablish the flow of coolant from the troughs to the base of the peripheral recess.
Russian patent 872,234 discloses a similar grinding wheel assembly, wherein apertures are provided in the wheel flanges to allow a flow of cooling fluid from trough-shaped channels to the base of the grindstone. These apertures may also become blinded by particles abraded from the workpiece.
U.S. Pat. No. 3,417,517 to Rose discloses a grinding apparatus, wherein water is supplied through passages in a grinding wheel flange to the inner peripheral surface of the porous grinding wheel.
It would be desirable to prepare a grinding wheel assembly, wherein a fluid may be delivered to the point of contact between the grinding wheel and the workpiece via apparatus having a configuration which does not easily become blinded by abraded particles and which may easily be cleaned and reused.